What does untrustworthy mean?
Untrustworthy means that someone or something cannot reasonably be trusted. The word is used for people, organizations, sources, information, and systems whose claims, behavior, or performance cannot be relied upon. Its strong negative connotation often suggests dishonesty or bad faith, although it can also describe a source that is simply inaccurate or a mechanism that fails unpredictably. In everyday use, calling a person untrustworthy is a serious moral judgment, whereas calling a machine or process untrustworthy may focus more on inconsistency or unreliability. The adjective is common in news reporting, legal contexts, consumer advice, and personal criticism. It is often more emphatic than unreliable, making it useful when the speaker wants to communicate not merely that something may fail but that it should not be accepted as dependable. Untrustworthy is also a useful contrast with trustworthy, which means worthy of confidence and reliance.
adjectiveNot trustworthy; unable or unlikely to be relied upon. The word often implies dishonesty, unreliability, or a strong reason for distrust.
- Unable or unlikely to be trusted; regarded as dishonest, unreliable, or otherwise undeserving of confidence.
"Because the source had repeatedly published false information, many readers considered it untrustworthy."
"The investigator dismissed the untrustworthy witness's account of the incident."
"Consumers should be cautious when relying on untrustworthy reviews to make a purchase decision."
The prefix does the heavy lifting: untrustworthy is a trust with a warning label attached.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does untrustworthy come from?
Untrustworthy is an English adjective formed by adding the negative prefix un- to trustworthy, a compound built from trust and -worthy. The prefix un- has Old English roots and was historically used to negate adjectives, while the underlying idea of being worthy of trust gives the modern word its sense. Related formations such as trust, trusty, trustee, and trusteeship preserve the same central root, although untrustworthy specifically developed as a negated form of trustworthy.
Related word forms
How untrustworthy is actually used
This is a strongly negative adjective used in both formal and informal contexts. It is often more judgmental than simply saying that someone or something is inconsistent, and it can suggest deception, bad faith, or repeated failure to meet expectations.
Easily confused with untrustworthy
An unreliable person or thing may be inconsistent or fail to work as expected, whereas an untrustworthy one is considered dishonest or unfit to be trusted.